Although used universally and informatively to obtain immunohistochemical pathology data, the invaluable clinical resource in the form of archival formalin-fixed, paraffin-embedded tissues is under-utilized due to restricted ability to effectively retrieve proteins, DNA and RNA. Improvements in the techniques to maximize extraction of these bio-molecules are, therefore, critical to the field of cancer research, which would enable effective combination of classical pathology and modern molecular biology techniques to accomplish retrospective molecular morphology studies. The studies proposed in this application are aimed at achieving substantial improvements in yield of all these three macromolecules from stored fixed tissues. The philosophy of retrieval has its foundation in the exhaustive research work pioneered by this laboratory in rendering otherwise inaccessible bio-molecules available for immunohistochemical staining on archival fixed tissue sections. The basic chemical reactions of formalin with protein and nucleic acid include a replacement of amino or imino groups in peptides and nucleotides by hydroxymethyl group. This is followed by secondary condensation reaction for both proteins and nucleic acids, resulting in the formation of a stable methylene compound.